Global warming isn’t a myth, and the impacts of dumping loads of greenhouse gasses are becoming more and more prevalent as time progresses. With rising sea levels due to the melting of arctic sea ice, time becomes scarce for humans to cut down on their emissions before the world is forever changed. In the marine science community, a devastating reality surfaced recently; the Great Barrier Reef is dying at an alarming rate due to ocean acidification. Binding with carbonate molecules is sequestering increased levels of CO2 into the water column lowers the pH of water, while also impeding calcification rates. Essentially, corals and shellfish are having difficulty maintaining their calcium-based shells, as higher acidities are dissolving their shells faster than they can build them back up.
In December of 2017, I along with 20 classmates from Boston University traveled to Belize to study changes in marine life. More specifically, my group looked into coral species’ popularity on reefs surrounding the Calabash Cay Island. It was an eye opening experience. I conducted a short interview with a classmate concerning ocean acidification; “The Ocean acts as a carbon ‘sink’ absorbing atmospheric carbon dioxide. When atmospheric CO2 increases, so do levels of ocean CO2. When the CO2 is in the water, chemical reactions occur that reduce pH. This has a negative effect on animals that rely on calcium carbonate for their skeletons and shells, as the reactions reduce the amount of calcium carbonate available.” –Kendall McPherson BU 18’. Generally, atmospheric influence on the ocean’s biochemistry is a one-way street. With increasing concentrations of carbon dioxide being thrusted into the atmosphere, more and more of this greenhouse gas moves into the ocean. This has a particularly bad effect in high CO2 concentrated waters, as shellfish require a high calcification rate in order to maintain their shells. The impact of increased CO2 concentrations has become more noticeable to the public in the last decade, with the largest reef in the world bleaching at alarming rates. What many people don’t know about coral is that coral is actually only living on the outer layer of its structure. As coral dies, new polyps grow over the dead and solidified coral. However, when these polyps die, they reveal the white “bleached” coral skeleton beneath.
Now you may be wondering, specifically how do more acidic ocean conditions affect coral? Surface waters naturally absorb carbon dioxide, where it undergoes a chemical reaction with water to form Bicarbonate and Hydrogen ions. Corals and other organisms use calcium carbonate as a skeleton for structural integrity, and maintain themselves by constantly replacing CaCO3 (calcium carbonate) lost to normal ocean acidity. However, with more carbon dioxide being expelled into the atmosphere, hydrogen ion concentrations rise as CO2 and H2O react. This increase in H+ (hydrogen ion) concentrations results in an imbalanced system, and corals and other shellfish are unable to maintain their shells to a favorable efficiency. Higher concentrations of hydrogen ions result in acidic water conditions. As a result, the acidic water begins to kill off the outer layer of polyps that exist on the coral, leaving the white “bleached” coral skeleton exposed.
Organizations like Soli offer different methods of environmental conservation that could make an impact on the mortality rates that is affecting our world’s coral reefs. Soli helps keep carbon dioxide out of the atmosphere by using carbon credits, which are lowered when university students use the Soli app to make purchases with Soli vendors. Carbon credits can reduce the overall output of CO2, which in turn can give reefs a fighting chance to survive acidic water conditions. Soli purchases carbon credits as students use the Soli app to make every day purchases at places such as Panera Bread.
For example; Sally, a Boston University student, buys dinner at Shawarma King. For each $1 spent using the Soli app, 2 pounds of carbon credits are permanently retired. At the same time, her purchase gives her the option to receive cash back or to donate the cash back to a nonprofit of her choice or to Climate Remediation Foundation. Imagine if each university could get students to sign up for and use the Soli app! On a much larger scale, with much of the student population shopping using the Soli app, the carbon footprint for Boston University alone can greatly impact the atmosphere. It’s time for all college students to make a difference. If you would like to learn more about Carbon Dioxide and its effects on coral reefs, visit the links below.
https://www.nature.com/articles/nclimate1122
http://science.sciencemag.org/content/318/5857/1737